Solid-state power switches, in particular field-effect controlled switching devices such as a Metal Oxide Semiconductor Field-effect Transistor (MOSFET) or an Insulated Gate Bipolar Transistor (IGBT), have been used for various applications, including, but not limited to, use as switches in power supplies and power converters, electric cars, air-conditioners, and even electrical grids used by renewable energy suppliers. Particularly with regard to power devices capable of switching large currents and/or operating at higher voltages, controlling solid-state power switches in such devices can be based on different designs of driver circuits.
Typically, such driver circuits are operated in a low-voltage region, whereas the solid-state power switches are operated at high voltages. Furthermore, driver circuits included in high power switching devices are designed for controlling solid-state switches that have positive or negative control voltages. The gate voltages for power switches can be positive or negative. Conventionally, driver circuits are connected to logic circuits providing control signals for the driver circuit connected to the respective logic circuit. Typically, both the logic circuits and the driver circuits are operated in the low-voltage region.
Different functional components, such as logic circuits, driver circuits and solid-state power switches, can be manufactured by means of different technologies, resulting in different pieces of semiconductor substrates. Typically, logic circuits and driver circuits are silicon-based, wherein the respective substrate is directly connected to ground, e.g., to improve cooling of the respective component. For solid-state power switches based on silicon, vertical arrangements with a drain terminal at a backside and gate/source terminals at a front side can be used. For higher switching frequencies and higher power density, wide-bandgap-based solid-state power switches such as SiC-JFETs or GaN-HEMTs switches can be used. These devices can be designed as normally-on devices, which can be manufactured—for a given blocking voltage and a given on-resistance—up to ten times smaller in chip size than comparable solid-state power switching devices based on silicon, which are usually normally-off devices. As a current flow in these devices is parallel to a substrate surface, these devices can be setup with source terminal at the backside and gate/drain terminals at the front side of the substrate. For high frequencies and efficient cooling during high current operation, short connections with low inductance, large connection areas between the different functional components, and a high integration density are desired.
In view of the above, there is a need for improving driver configuration for high-voltage switches.